Cassini is a joint mission of NASA, the European Space Agency, and the Italian Space Agency. The original mission was intended for just four years. The original mission has been extended twice to the present day. The images and scientific data returned by Cassini have added immensely to our knowledge of the science of gas giant planets.

Technically, the mission is named Cassini-Huygens. On Christmas Day, 2004, the Huygens probe detached from Cassini. Huygens landed on Titan, Saturn’s largest moon on January 14, 2005, the first landing on a moon in the outer Solar System.

The main probe was named for Giovanni Cassini, an Italian mathematician and astronomer. He discovered four of Saturn’s moons and was the first director of the Paris Observatory.

The Titan lander was named for Christiaan Huygens, a Dutch mathematician and scientist who studied the rings of Saturn and discovered Titan.

While the mission life has far exceeded the original plan, Cassini is coming to an end. It no longer has sufficient fuel to maintain orbital stability.

On April 22, 2017, Cassini began the first of 22 Grand Finale orbits with one final close flyby of Titan. These orbits will take Cassini BETWEEN the rings and the planet, a gap of just 1,500 miles. This will allow analysis of Saturn’s atmosphere in more detail than ever before. The probe’s cameras will capture the closest images ever taken of the rings and Saturn’s atmosphere.

On September 15, thirteen years into a planned four-year mission, Cassini will complete its final orbit. The gravity from distant Titan will shift the orbit sufficiently such that Cassini will enter Saturn’s upper atmosphere and disintegrate.